So I'm single and dating again

My girlfriend of 6 months was no longer into non-monogamous dating. It was hard finding a date while having a girlfriend. But when I finally found a date, she dumped me. She had said she was OK with an open relationship I guess until I actually wanted to go on a date. It's OK. That's her right to break things off. Nobody has a right to be with somebody else. I can accept that.